There are 4 biology questions in the second year of junior high school, and a few practice questions

4.Articular surfaces.

Reason for selection: Aggressive behavior is generated by the struggle between individuals of the same species for living space and living conditionsIn the animal kingdom, individuals of the same species often attack or fight each other over food, mates, territory, or nesting area, and this behavior is called aggression.

Bioreactor: A bioreactor is a device system that uses the biological functions of enzymes or organisms (such as microorganisms) to carry out biochemical reactions in vitro, and is a kind of biological function simulation machine, such as fermenters, immobilized enzymes or immobilized cell reactors.

Bioreactor has gone through three stages of development: bacterial genetic engineering, cell genetic engineering, and transgenic animal bioreactor. The emergence of transgenic animal bioreactors has attracted great attention because it overcomes the defects of the first two, that is, cell genetic engineering products are often not biologically active, and must undergo a series of modifications such as glycosylation and hydroxylation before they can become effective drugs, while cell genetic engineering limits large-scale production because the culture conditions of mammalian cells are quite demanding and the cost is too high.

In addition, the transgenic animal bioreactor also has the characteristics of high product quality and easy purification. Generally, transgenic animals whose target fragments are expressed in organs or tissues are called animal bioreactors. Almost any living organ, tissue, or part of it can be domesticated into a bioreactor.

From the perspective of production, the tissues or organs selected by the bioreactor should facilitate the acquisition of products, such as mammary glands, bladder, blood, etc., so the animal mammary gland bioreactor, animal blood bioreactor and animal bladder bioreactor have been developed. Among them, the research on mammary gland bioreactors of transgenic animals is the most eye-catching.

4.Articular surface The opposite surface of the two bones that make up the joint is called the articular surface, which is generally one convex and one concave to adapt to each other. The convex one is called the joint head, and the concave one is called the joint socket.

The articular surface is covered by articular cartilage, and except for a few joints (sternoclavicular joint, mandibular joint), the articular cartilage is fibrocartilage, and the rest are hyaline cartilage. Articular cartilage makes the shape of the joint head and socket more adaptable, its surface is smooth, there is a little synovial fluid between the surfaces, the friction coefficient is less than that of the ice surface, so it makes the movement more flexible, and because the cartilage is elastic, it can bear the load and slow down**. Articular cartilage has no vascular nerve distribution and is nourished by vascular osmosis of synovial fluid and synovial layer of the joint capsule.

The basic structure of the joint includes: articular surface, articular cavity, and joint capsule.

Articular cavity, articular surface, articular capsule.

Articular surface, articular cavity, articular capsule.

c c c articular cavity, articular surface, articular capsule.

a c c articular cavity, articular surface, articular capsule.

1 Dirty clothes are easy to mold, not because there is a suitable temperature than the clean ones, but because there are stains on the dirty clothes, and those stains contain nutrients needed for bacterial growth.

2 Weight and specific gravity are not the same, specific gravity is the ratio of weight to volume, that is, density. The balloon gyback reduces the specific gravity of the body because of the increased volume.

3. Breaking the ecological balance and violating national laws.

4 Errors. Judgments that can be overturned by one condition are all wrong.

1.Dirty clothes have organic matter on them (such as oil stains, etc.), as well as inorganic substances needed for growth, and most of the organic matter will oxidize in the air with the formation of water needed for mold growth, and the air is also made of water! Generally, mold can grow at room temperature (and high temperature will kill some mold, but low temperature will only inhibit the growth rate and will not kill mold), so it is best for mold to grow on dirty clothes.

2.Specific gravity and weight are two completely different concepts, like density and mass. Can you say that dense iron is definitely heavier than less dense wood?

3.I don't understand what you are asking, the illegal capture of wild animals or the indiscriminate killing of endangered animals and the destruction of biological habitats... Embarrassment.

4.Electromagnetism in the second year of junior high school is still relatively simple, and these should be answered according to the situation Outside the power supply, the current flows from the positive electrode to the negative electrode, since there is already a current generated above, it means that it is indeed a closed loop (that is, what you call circuit closure. It's a term for high school, a term.

The premise of the physics book is that the circuit is closed before there is current.

Middle School: c. Biologically, the basic unit of species is the species. That is, a species is a living organism.

Similar morphological structure and physiological function are not necessarily the same species, just like flowers, different flowers have the same basic structure and the same function (reproduction).

2.The same distribution is not necessarily the same species, such as tens of thousands of species of tropical fish.

High School Theory: A species is a living thing.

Species are the basic units of taxonomy.

The existence of the same species and subspecies that are reproductively isolated from other similar groups is called reproductive isolation in interspecific isolation, that is, there are no homologous chromosomes.

And occupy a certain ecological niche in nature.

d is wrong species can be considered to be a species of genus and species of the phylum family, then a obviously treats the species as an individual wrong, b species must first form a genus and cannot directly form a family, c a creature is not a species, obviously correct, for d, a group of organisms with similar morphological structure and physiological function performance, and the ecological distribution is basically the same may be different species, because the said shi performance is similar For example, two subspecies may have this kind of acquaintance, but the metabolism is different and it can still be divided into different species, Plus a bunch of the word is very inaccurate.

Species are the basic units of taxonomy. A species is a natural group formed by the same organisms that reproduce with each other, are reproductively isolated from each other and occupy a certain ecological niche in nature.

D is problematic. For example, silkworms and earthwormsThe morphological structure and physiological function are similar, and the ecological distribution is basically the same, but they are not the same species.

1) If you want to think about the effect of light on corn seed germination, how do you think you should design the experiment? Answer: Important (experimental group and control group, compare the effect of light on corn seed germination) (2) When transplanting corn seedlings, you need to bring soil mounds, and what is the purpose of this?

Answer: In case of damage to fibrous roots. (3) In order to ensure the survival rate, it is often transplanted on cloudy days or in the evening, why is this done?

Answer: Reduce the transpiration of the tree. (4) When breaking the corn ears, it is often found that the corn ears have a lack of grains, what is the reason?

A: Genetic or pest. In order to avoid this phenomenon, Li Denghai, who is known as the "king of corn", has cultivated a series of "compact hybrid corn" to achieve high yields.

This rational dense planting method ensures the leaves of corn (benign genetics), thereby increasing the yield of corn; In order to avoid the occurrence of this phenomenon, (biological control) methods can be used to compensate. Students from a biology group planted peanuts in a school's experimental field, and their following practices were not meaningful for peanut germination: (c)aSow b. on a sunny day

Sow seeds in the spring cSow after the rain DSow seeds after loosening the soil (teething does not require too much water, light is very important), please ask if you don't understand, thank you.

(1) Put the same amount of moist cotton in the same two beakers, and then put the same amount of corn seeds on top, one beaker in the light of 25, and one beaker in the dark environment of 25. (2) Protect the root hairs in the mature area (3) In order to reduce the transpiration of plants (4) Insufficient pollination Fully receive light and improve the efficiency of photosynthesis Artificially assisted pollination aSow on a sunny day.